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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Moderate temperature Na cells. III - Electrochemical and structural studies of Cr0.5V0.5S2 and its Na intercalates

Experimental results are reported on the behavior of a rechargeable Na cell incorporating a Cr0.5V0.5S2 cathode. The cell operates at 130 C and uses as electrolyte a 1M solution of NaI in 1,2-bis(2-methoxy-ethoxy)ethane (triglyme). The mechanism of discharge of Cr0.5V0.5S2 involves Na intercalation. It is found that the maximum rechargeable capacity of the Cr0.5V0.5S2 cathode is 0.7 e(overbar)/mol. With an average cell voltage of 1.9 V, the theoretical specific energy of the cathode is 273 W-hr/kg.

Abraham, K. M.↗
NASA NTRS1982

Deep Discharge Reconditioning and Shorted Storage of Batteries

The identification and measurement of hydrogen recombination in sealed nickel-cadium cells makes deep reconditioning on a battery basis safe and feasible. Deep reconditioning improves performance and increases life of nickel-cadium batteries in geosynchronous orbit applications. The hydrogen mechanism and supporting data are presented. Parameter cell design experiments are described which led to the definition of nickel-cadium cells capable of high rate overdischarge without detriment to specific energy. Nickel-cadium calls of identical optimum design were successfully cycled for 7 seasons in simulation of geosynchronous orbit at 75 percent depth-of-discharge with extensive midseason and end-of-season overdischarge at rates varying from C/20 to C/4. Destructive physical analysis and cyclin data indicated no deterioration or the development of dangerous pressures as a result of the cycling with overdischarge.

Ritterman, P. F.↗
NASA NTRS1983

Development of a condenser for the dual catalyst water recovery system

Conceptual evaporation/condensation systems suitable for integration with the catalytic water recovery method were evaluated. The primary requirements for each concept were its capability to operate under zero-gravity conditions, condense recovered water from a vapor-noncondensable gas mixture, and integrate with the catalytic system. Specific energy requirements were estimated for concepts meeting the primary requirements, and the concept most suitable for integration with the catalytic system was proposed. A three-man rate condenser capable of integration with the proposed system, condensing water vapor in presence of noncondensables and transferring the heat of condensation to feed urine was designed, fabricated, and tested. It was treated with steam/air mixtures at atmospheric and elevated pressures and integrated with an actual catalytic water recovery system. The condenser has a condensation efficiency exceeding 90% and heat transfer rate of approximately 85% of theoretical value at coolant temperature ranging from 7 to 80 deg C.

Budinikas, P.↗
NASA NTRS1984

Characteristics of a microwave plasma disk ion source

This letter describes an ion source using a cylindrical microwave cavity operating in a hybrid mode associated with the TE(211) empty cavity mode. The design principles and associated electrical systems are also discussed. Extracted beam current versus accelerating voltage, and specific energy versus extracted beam current are displayed over the range of flow rates 20-80 sccm and absorbed powers 80-150 W. The results show the feasibility of this concept. The ion source has many potential uses such as space propulsion, material processing, and neutral beam ion sources.

Asmussen, J.↗
NASA NTRS1984

Development of a preprototype times wastewater recovery subsystem, addendum

Six tasks are described reflecting subsystem hardware and software modifications and test evaluation of a TIMES wastewater recovery subsystem. The overall results are illustrated in a figure which shows the water production rate, the specific energy corrected to 26.5 VDC, and the product water conductivity at various points in the testing. Four tasks are described reflecting studies performed to develop a preliminary design concept for a next generation TIMES. The overall results of the study are the completion of major design analyses and preliminary configuration layout drawings.

Dehner, G. F.↗
NASA NTRS1984

Recent work on a microwave ion source

The performance of a microwave (2.45 GHz) plasma-disk ion source using a cylindrical microwave cavity is described. The operating characteristics in argon and xenon gases with 50-200 W of input power and gas flow rates from 10-80 sccm are presented. In particular, extracted beam current versus accelerating voltage, and specific energy vs. mass utilization efficiency and extracted beam current are presented. Double Langmuir probe measurements indicate that electron densities in excess of 10 to the 12th per cu cm can be readily achieved in the microwave generated plasma.

Asmussen, J.↗
NASA NTRS1984

The NASA Lithium Technology Program

NASA is sponsoring research to develop advanced primary and secondary lithium cells. Lithium cells are conducive to aerospace use because they have high specific energy, volumetric energy density, and long storage capability. The primary cell research is centered on the Li/SOCl2 system. It is in the late development stage and all effort is being placed on resolving safety problems. The secondary cell, which is in the development stage, is the Li/TiS2 system. The objective is to produce a 100 wh/kg cell capable of operating in a geosynchronous orbit for 10 years. The development of improved conductivity polymeric films for electrochemical use is also being investigated. The lightweight batteries will have many applications in space and are already being prepared for the 1986 Galileo mission to Jupiter.

Halpert, G.↗
NASA NTRS1985

Phase change water processing for Space Station

The use of a vapor compression distillation subsystem (VCDS) for water recovery on the Space Station is analyzed. The self-contained automated system can process waste water at a rate of 32.6 kg/day and requires only 115 W of electric power. The improvements in the mechanical components of VCDS are studied. The operation of VCDS in the normal mode is examined. The VCDS preprototype is evaluated based on water quality, water production rate, and specific energy. The relation between water production rate and fluids pump speed is investigated; it is concluded that a variable speed fluids pump will optimize water production. Components development and testing currently being conducted are described. The properties and operation of the proposed phase change water processing system for the Space Station, based on vapor compression distillation, are examined.

Zdankiewicz, E. M.↗
NASA NTRS1985

Rotor stresses in a magnetically suspended flywheel system

A stress analysis of a composite-based multiring/multiwheel flywheel system for space applications is described. It is shown that the specific energy density (SED) of a given flywheel system geometry can be increased by a factor of two or more by means of an interference assembly. Radial stresses in the interference assembly are redistributed in such a way that the outer flywheel rings will separate at their interfaces when the critical flywheel speed is exceeded. It is pointed out that proper use of this condition can reduce the containment weight requirements of flywheel systems in general.

Kirk, J. A.↗
NASA NTRS1986

Examination of design options for 35 Ah ambient temperature Li-TiS sub 2 cells

The Jet Propulsion Laboratory is actively engaged in the development of ambient temperature rechargable lithium cells for future NASA geosynchronous Earth orbit (GEO) missions. To achieve these ambitious goals, Li-TiS2, Li-MoS3, and Li-V6O13 systems were examined in detail. Among these three, the Li-TiS2 system has shown the longest life cycle and highest rate capability. Experimental Li-TiS2 batteries (10.5 V, 0.4 Ah) developed in-house have completed eight simulated and accelerated GEO seasons successfully. Inview of the encouraging results, the design options were examined for a scaled-up Li-TiS2 cell. It is hoped that the results of these studies will provide guidelines for prioritizing the research efforts and guiding the selection of optimized materials. Designs for 35 Ah Li-TiS2 cell were examined because present day geosynchronous satellites are powered by batteries of 35 Ah capacity. A computer program was developed to evaluate the influence of various design parameters on the specific energy and the rate capability of the cells.

Shen, D. H.↗
NASA NTRS1986

The 4.5 inch diameter IPV Ni-H2 cell development program

Interest in larger capacity Ni-H2 battery cells for space applications has resulted in the initiation of a development/qualification/production program. Cell component design was completed and component hardware fabricated and/or delivered. Finished cell design projections demonstrate favorable specific energies in the range of 70 to 75 Whr/Kg (32 to 34 Whr/Lb) for capacities of 100 to 250 Ah. It is further planned during this effort to evaluate the advanced cell design technology which has evolved from the work conducted at the NASA/Lewis Research Center.

Miller, L.↗
NASA NTRS1987

Development of control strategies for safe microburst penetration: A progress report

A single-engine, propeller-driven, general-aviation model was incorporated into the nonlinear simulation and into the linear analysis of root loci and frequency response. Full-scale wind tunnel data provided its aerodynamic model, and the thrust model included the airspeed dependent effects of power and propeller efficiency. Also, the parameters of the Jet Transport model were changed to correspond more closely to the Boeing 727. In order to study their effects on steady-state repsonse to vertical wind inputs, altitude and total specific energy (air-relative and inertial) feedback capabilities were added to the nonlinear and linear models. Multiloop system design goals were defined. Attempts were made to develop controllers which achieved these goals.

Psiaki, Mark L.↗
NASA NTRS1987

Na/beta-alumina/NaAlCl4, Cl2/C circulating cell

A study was made of a high specific energy battery based on a sodium negative electrode and a chlorine positive electrode with molten AlCl3-NaCl electrolyte and a solid beta alumina separator. The basic performance of a Na beta-alumina NaAlCl4, Cl2/C circulating cell at 200 C was demonstrated. This cell can be started at 150 C. The use of melting sodium chloroaluminate electrolyte overcomes some of the material problems associated with the high working temperatures of present molten salt systems, such as Na/S and LiAl/FeS, and retains the advantages of high energy density and relatively efficient electrode processes. Preliminary investigations were conducted on a sodium-chlorine static cell, material compability, electrode design, wetting, and theoretical calculations to assure a better chance of success before assembling a Na/Cl2 circulating cell. Mathematical models provide a theoretical explanation for the performance of the NaCl2 battery. The results of mathematical models match the experimental results very well. According to the result of the mathematical modeling, an output at 180 mA/sq cm and 3.2 V can be obtained with optimized cell design.

Cherng, Jing-Yih↗
NASA NTRS1987

The line integral approach to radarclinometry

Advances over previous work in radarclinometry (Wildey, 1984 and 1986) are proposed, including incorporation of a more exact treatment of the dependence on terrain orientation of the solid angle of integration of the microwave specific energy comprising individual pixel power, and the integration of the theory in the cross-ground-range direction. The local curvature hypothesis, making possible formulation of the theory in terms of a line integral, is expanded to include the possibilities of local cylindricity, local biaxial ellipsoidal hyperbolicity, and least-squares local sphericity. It is suggested that the banding noted in topographic maps which are produced on the basis of variation in the proportioning between curvature assumptions may be due to the lack of radiometric calibration.

Wildey, Robert L.↗
NASA NTRS1987

Vapor Compression Distillation Subsystem (VCDS) component enhancement, testing and expert fault diagnostics development, volume 1

Vapor compression distillation technology for phase change recovery of potable water from wastewater has evolved as a technically mature approach for use aboard the Space Station. A program to parametrically test an advanced preprototype Vapor Compression Distillation Subsystem (VCDS) was completed during 1985 and 1986. In parallel with parametric testing, a hardware improvement program was initiated to test the feasibility of incorporating several key improvements into the advanced preprototype VCDS following initial parametric tests. Specific areas of improvement included long-life, self-lubricated bearings, a lightweight, highly-efficient compressor, and a long-life magnetic drive. With the exception of the self-lubricated bearings, these improvements are incorporated. The advanced preprototype VCDS was designed to reclaim 95 percent of the available wastewater at a nominal water recovery rate of 1.36 kg/h achieved at a solids concentration of 2.3 percent and 308 K condenser temperature. While this performance was maintained for the initial testing, a 300 percent improvement in water production rate with a corresponding lower specific energy was achieved following incorporation of the improvements. Testing involved the characterization of key VCDS performance factors as a function of recycle loop solids concentration, distillation unit temperature and fluids pump speed. The objective of this effort was to expand the VCDS data base to enable defining optimum performance characteristics for flight hardware development.

Kovach, L. S.↗
NASA NTRS1987

The crucial role of cooling in the making of molecular clouds and stars

The role that velocity or pressure fluctuations in the H I clouds medium can play in initiating compression of sub-Jeans mass diffuse clouds is outlined. The frequently discussed idea is reviewed that substantial overpressures arising in the warm, medium and/or highly supersonic compressions of H I clouds can push sub-Jeans mass clumps to densities where gravity can take over and complete the star formation process. A nonequilibrium model is used to analyze the impact of external disturbances on gas clouds, and estimates of the required disturbance amplitudes are substantially reduced from previous estimates based on equilibrium arguments. The results reveal that a cloud which cools under compression is particularly sensitive to mild disturbances from its environment. Furthermore, the specific energy required to trigger effective compressions in a cooling medium is nearly independent of the cloud's mass. It is proposed that mildly nonlinear disturbances play a primary role in the formation of molecular cloud and stars.

Tohline, Joel E.↗
NASA NTRS1989

A survey of advanced battery systems for space applications

The results of a survey on advanced secondary battery systems for space applications are presented. The objectives were: to identify advanced battery systems capable of meeting the requirements of various types of space missions, with significant advantages over currently available batteries, to obtain an accurate estimate of the anticipated improvements of these advanced systems, and to obtain a consensus for the selection of systems most likely to yield the desired improvements. Few advanced systems are likely to exceed a specific energy of 150 Wh/kg and meet the additional requirements of safety and reliability within the next 15 years. The few that have this potential are: (1) regenerative fuel cells, both alkaline and solid polymer electrolyte (SPE) types for large power systems; (2) lithium-intercalatable cathodes, particularly the metal ozides intercalatable cathodes (MnO2 or CoO2), with applications limited to small spacecrafts requiring limited cycle life and low power levels; (3) lithium molten salt systems (e.g., LiAl-FeS2); and (4) Na/beta Alumina/Sulfur or metal chlorides cells. Likely technological advances that would enhance the performance of all the above systems are also identified, in particular: improved bifunctional oxygen electrodes; improved manufacturing technology for thin film lithium electrodes in combination with polymeric electrolytes; improved seals for the lithium molten salt cells; and improved ceramics for sodium/solid electrolyte cells.

Attia, Alan I.↗
NASA NTRS1989

Multi-mission Ni-H2 battery cell for the 1990's

A sufficient production, test and operational database is now available to permit design technology optimization for the next decade. The evolved battery cell design features standardized technology intended to support multiple type missions (e.g., both GEO and LEO). Design analyses and validation test cells demonstrate improved performance plus attractive specific-energy characteristics will be achieved.

Miller, Lee↗